For many years now, I have been travelling with PowerBooks and have left them in hotel rooms locked up (attached to something non-removable or too heavy/big to remove), with a Kensignton-type device made by Belkin and featuring a combination lock (not a key). Never had a problem. That's why I said the little socket is essential, as we are talking about a computer that has been made to take around (not to sit on desk at home - at least, primarily).